The PlayStation 3 has a Gigabit Ethernet port (all models except one include Wi-Fi to connect wirelessly via an Access Point), allowing connection to the internet for websurfing and downloading games off of the PlayStation Store. The Fat PS3 Ethernet controller is a Marvell 88E6108 chip, while the Slim PS3 is a Marvell Alaska 88E111R chip. If Wi-Fi is supported in the PS3, then you can also use the PSP to control and view PS3 content and games.
The PS3 only supports HTTP and HTTPS proxy (which means no SOCKS proxy of any version) if you elect to use a proxy address in the network connection settings. Because of this, some PS3 socket communications that do NOT access websites (connections that don't use http port 80 or https port 443 for example) will end up bypassing your proxy settings and directly connect to the internet.
The PS3 allows you to connect to the internet via three NAT (Network Address Translation) modes.
NAT Type 1:
Your PS3 is connected directly to your modem (usually via ADSL PPPoE), and sending the user name and password for getting a connection (public ip address).
NAT Type 2:
Your PS3 is connected to your router. The router is connected to your modem (usually via ADSL PPPoE). The router is giving your PS3 an internal ip address after sending the user name and password for getting a connection (public ip address).
NAT Type 3:
Your PS3 is connected to your router. The router is connected to your modem (usually via ADSL PPPoE). The router is giving your PS3 an internal ip address after sending the user name and password for getting a connection (public ip address). However, ports are not forwarded to your PS3.
Normally if you are using a connection of NAT Type 3, you may need to manually forward ports to your PS3. The following are ports that are required for the PS3 to operate:
PSN requires these open ports: TCP: 80, 443, 5223. UDP: 3478, 3479, 3658.
PS2 games requires these open ports: UDP: 4658, 4659
PSP Remote Play requires this open port: TCP 9293.
Universal Plug and Play (UPnP)
Because of the difficulty of memorizing what devices (or game and app) use which ports, and manually opening and forwarding ports on your router, UPnP was created. If your router and device (like PS3) supports UPnP, simply enabling this option will let the device (or app and game) directly tell the router what ports needs to be opened and forwarded to the device for it to work. Turning this option on in the PS3 and router (assuming it supports it), will solve most problems automatically.
DLNA (Digital Living Network Alliance)
The PS3 supports being a recipient of streamed video or audio content. It does this via supporting the DLNA protocol. To enable this feature, simply have a server (a computer running Linux or Windows) running an application (like Windows Media Player) that support DLNA. Make sure your PS3 and this server are both connected to the same router (so NAT Type 1 won't work). Simply make the application serving music or videos share some content, and ask the PS3 to look for DLNA content from the XMB.